Microbial strain data are being entered into a data bank with the objective of generating a system for providing such services as data on specific organisms and/or groups of organisms, a locator service for strains with special characteristics, identification of unknown isolates, cluster analysis definition of parameters of taxa, data management and report writing aids for research purposes, aids in quality control of tests, methods, and laboratories, and communication of data via common format. A data file of primary data on a large number of bacteria and yeasts found in the oral cavity and related types is being established. This file will provide a resource for asking both ecological and epidemiological questions of interest in dental research. Programs are being developed and tested to enter, retrieve, and analyze the data in a variety of ways for epidemiological, diagnostic, taxanomic, ecological etc. uses. The long term goal is to establish a world-wide data bank at a series of cooperating centers. The system originally developed for bacteria is now being expanded to include the yeasts, mold and protozoa. A series of monographs describing the expanded system is in varying stages of preparation. (1) Microbiology Department, University of Maryland, College Park, Md. (2) American Type Culture Collection, Rockville, Md. (3) University of Queensland, Brisbane, Australia. (4) Forsyth Dental Center, Boston, Massachusetts. (5) Central Public Health Laboratory, London. (6) VA Hospital, Miami, Florida.